Ruby support for Source Maps allows you to interact with Source Maps in Ruby. This
lets you do things like concatenate different javascript files and still debug them
as though they were separate files.
See the spec for more information:
https://docs.google.com/document/d/1U1RGAehQwRypUTovF1KRlpiOFze0b-_2gc6fAH0KY0k/edit